2121565820 has 48 divisors (see below), whose sum is σ = 4973367168. Its totient is φ = 753533760.

The previous prime is 2121565811. The next prime is 2121565841. The reversal of 2121565820 is 285651212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 102674 + ... + 121593.

It is an arithmetic number, because the mean of its divisors is an integer number (103611816).

Almost surely, 2^2121565820 is an apocalyptic number.

2121565820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2121565820 is an abundant number, since it is smaller than the sum of its proper divisors (2851801348).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2121565820 is a wasteful number, since it uses less digits than its factorization.

2121565820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224330 (or 224328 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 32.

The square root of 2121565820 is about 46060.4583129608. The cubic root of 2121565820 is about 1284.9478537687.

The spelling of 2121565820 in words is "two billion, one hundred twenty-one million, five hundred sixty-five thousand, eight hundred twenty".